Changes

All metabolism by Lactobacillus , including growth, will require sugar to be consumed and lactate (lactic acid) to be produced, including growth. Two categories of metabolism exist, '''homofermentative''' and '''heterofermentative'''. ''Homofermentative'' metabolism is described as the cell catabolizing one molecule of glucose to yield two molecules of pyruvate, which is reduced to two molecules of lactate (lactic acid). ''Heterofermentative'' metabolism is described as the cell catabolizing one molecule of glucose into one molecule of CO2, one molecule of glyceraldehyde phosphate, and one molecule of acetyl phosphate. The molecule of glyceraldehyde phosphate is reduced to one molecule of lactate, and the acetyl phosphate is reduced to on molecule of ethanol. In summary, ''homofermentative'' LAB produces only lactic acid, while ''heterofermentative'' LAB produce lactic acid, CO2, and ethanol <ref>[http://textbookofbacteriology.net/lactics_2.html Todar's Online Texbook of Bacteriology. Kenneth Todar, PhD. Retrieved 05/06/2015.]</ref>.